Exam 2 Study Guide

Define Organ:

A structure composed of two or more tissue types that work together to perform a specific function.

Define Organism:

A living individual composed of multiple organ systems that work together to maintain life.

What are the 11 organ systems in the human body?

Integumentary, Skeletal, Muscular, Nervous, Endocrine, Cardiovascular, Lymphatic/Immune, Respiratory, Digestive, Urinary, Reproductive.

List the functions of the integumentary system:

Protection, temperature regulation, sensation, vitamin D production, and prevention of water loss.

The epidermis is made up of what type of tissue?

Keratinized stratified squamous epithelium.

Special characteristics of the epidermis:

Avascular, contains keratin, constantly regenerates, forms a protective barrier.

The dermis is made up of which tissue type?

Dense irregular connective tissue.

What types of fibers are found in the dermis?

Collagen fibers and elastic fibers.

Hair function:

Protection, insulation, and sensory detection.

Blood vessel function in skin:

Supplies nutrients and oxygen to skin tissues and helps regulate body temperature.

Sensory nerve endings function:

Detect touch, pressure, pain, and temperature.

Where is yellow bone marrow found?

In the medullary cavity of long bones.

Where is red bone marrow found?

In spongy bone, especially in flat bones and the epiphyses of long bones.

What is periosteum?

A dense connective tissue membrane that covers the outer surface of bones and contains blood vessels and nerves.

What is an osteon?

The structural unit of compact bone consisting of concentric layers of bone matrix surrounding a central canal.

Name the three cartilage types and list a location for each:

Hyaline cartilage (ends of bones or nose), elastic cartilage (ear), fibrocartilage (intervertebral discs).

What is the epiphyseal plate?

A growth plate made of cartilage located between the epiphysis and diaphysis where bone lengthening occurs during development.

Osteoblast function:

Cells that build new bone by producing bone matrix.

Osteoclast function:

Cells that break down bone tissue during bone remodeling.

Osteocyte function:

Mature bone cells that maintain bone tissue and communicate with other bone cells.

Which disease is due to a loss of bone mass after low activity and decrease in bone-building activities?

Osteoporosis.

Which bones are found in the axial skeleton?

Skull, vertebral column, ribs, and sternum.

Which bones are found in the appendicular skeleton?

Bones of the limbs and the shoulder and pelvic girdles.

What are the four types of bones?

Long bones, short bones, flat bones, and irregular bones.

How many ribs does each human have?

24 ribs (12 pairs).

Describe the type of mobility in each joint: Fibrous

No movement; bones are connected by dense connective tissue (example: skull sutures).

Describe the type of mobility in each joint: Cartilaginous

Limited movement; bones connected by cartilage (example: intervertebral discs).

Describe the type of mobility in each joint: Synovial

Freely movable joints with synovial fluid (example: knee or shoulder).

A trade off that occurs in joints is that the more flexible a joint is, the ______ stable the joint is.

Less stable.

Where are fontanels located? What is the function?

Located between the skull bones of infants; allow the skull to change shape during birth and permit brain growth.

Define ligament:

A strong band of connective tissue that connects bone to bone.

Define tendon:

A strong connective tissue that connects muscle to bone.

What is the function of Vitamin D in healthy bones?

It helps the body absorb calcium, which is necessary for bone formation and maintenance.

List the three types of muscle tissue: skeletal muscle

Skeletal muscle is attached to bones, striated, and voluntary.

List the three types of muscle tissue: cardiac muscle

Cardiac muscle is found in the heart, striated, and involuntary.

List the three types of muscle tissue: smooth muscle

Smooth muscle is found in walls of organs and blood vessels, non-striated, and involuntary.

Muscles that work together are known as _______.

Muscle synergists.

Muscles that oppose each other are known as _______.

Antagonists.

Define Origin:

The attachment point of a muscle that remains relatively stationary during contraction.

Define Insertion:

The attachment point of a muscle that moves during contraction.

The plasma membrane of a muscle fiber is known as the ___________.

Sarcolemma.

The endoplasmic reticulum of a muscle fiber is called the _______________.

Sarcoplasmic reticulum.

What are T-tubules? What is their function?

Invaginations of the sarcolemma that conduct action potentials deep into the muscle fiber to trigger calcium release.

What is a sarcomere? What structures mark the ends of the sarcomere?

The repeating contractile unit of a myofibril; the ends are marked by Z lines.

What protein make up thick filaments?

Myosin.

What proteins make up thin filaments?

Actin along with regulatory proteins troponin and tropomyosin.

What is the sarcolemma?

The plasma membrane of a muscle fiber that conducts action potentials.

What is the function of the sarcoplasmic reticulum?

Stores calcium ions and releases them during muscle contraction.

What causes the sarcomere to shorten during a contraction?

The sliding of actin thin filaments past myosin thick filaments during cross-bridge cycling.

What is the troponin-tropomyosin complex?

A regulatory protein system that blocks myosin binding sites on actin until calcium binds to troponin.

List the steps of muscle contraction in order:

Action potential reaches muscle fiber → sarcolemma and T-tubules conduct signal → sarcoplasmic reticulum releases Ca²⁺ → Ca²⁺ binds troponin → tropomyosin shifts exposing actin sites → myosin heads form cross bridges → power stroke pulls actin → ATP binds and resets the myosin head → cycle repeats.

Describe fast-twitch muscle fibers:

Contract quickly and powerfully, fatigue rapidly, rely more on anaerobic metabolism.

Describe slow-twitch muscle fibers:

Contract more slowly, resist fatigue, rely on aerobic metabolism and contain many mitochondria.

Define chemistry:

The study of matter, energy, and the interactions between them.

Define matter:

Anything that has mass and occupies space.

Define atom:

The smallest unit of an element that retains its chemical properties.

Define atomic number:

The number of protons in the nucleus of an atom.

Define atomic mass:

The total number of protons and neutrons in the nucleus.

Define energy:

The capacity to do work or cause change.

Define potential energy:

Stored energy that has the potential to perform work.

Define kinetic energy:

Energy of motion.

Ionic bond:

A chemical bond formed when electrons are transferred from one atom to another.

Example of ionic bond:

Sodium chloride (NaCl).

What happens with the electrons in an ionic bond?

One atom loses electrons and another gains them, creating oppositely charged ions.

Covalent bond:

A bond formed when atoms share electrons.

Polar covalent bond example:

Water (H₂O).

What happens with electrons in a polar covalent bond?

Electrons are shared unequally.

Nonpolar covalent bond example:

Oxygen gas (O₂).

What happens with electrons in a nonpolar covalent bond?

Electrons are shared equally.

Hydrogen bond:

A weak attraction between a hydrogen atom and another electronegative atom.

Hydrogen bond example:

Attraction between water molecules.

What happens with electrons in hydrogen bonds?

Electrons are not transferred; attraction occurs due to partial charges.

What four elements make up the largest contribution to the human body?

Oxygen, carbon, hydrogen, and nitrogen.

Define solute:

The substance being dissolved in a solution.

Define solvent:

The substance that dissolves the solute.

Define hydrophilic:

Substances that are attracted to and dissolve in water.

Define hydrophobic:

Substances that repel water.

pH is a measure of what in a solution?

The concentration of hydrogen ions.

Acid definition:

A substance that releases hydrogen ions and has a pH below 7.

Base definition:

A substance that accepts hydrogen ions and has a pH above 7.

Buffers function by ______ pH in solution.

Stabilizing or resisting changes in pH.

Dehydration synthesis __________ a water molecule to __________ a polymer.

removes; build

Hydrolysis __________ a water molecule to __________ a polymer.

Adds; break down

What are the functions of carbohydrates?

Provide quick energy and short-term energy storage.

What is a polymer of a carbohydrate called? Give an example:

Polysaccharide; example glycogen.

What is the function of lipids?

Long-term energy storage, insulation, cell membrane structure, and hormone production.

What is the difference between saturated fats and unsaturated fats?

Saturated fats have no double bonds and are solid at room temperature; unsaturated fats have double bonds and are usually liquid.

Which fat is solid at room temperature?

Saturated fat.

List functions of proteins:

Structure, enzymes, transport, signaling, movement, and immune defense.

What is a monomer of a protein called?

Amino acid.

What does it mean if a protein is denatured?

The protein loses its three-dimensional shape and cannot function properly.

Enzymes are important proteins that ______.

Catalyze chemical reactions by lowering activation energy.

Where are nucleic acids found?

In the nucleus and cytoplasm of cells.

What is the function of nucleic acids?

Store and transmit genetic information.

What are the four nitrogenous bases of DNA and how do they pair?

Adenine pairs with thymine, and cytosine pairs with guanine.

What are the four nitrogenous bases of RNA?

Adenine, uracil, cytosine, and guanine.

Define homeostasis:

The maintenance of a stable internal environment despite external changes.

Are negative or positive feedback loops more common?

Negative feedback loops are more common.

Example of negative feedback:

Body temperature regulation.

Example of positive feedback:

Labor contractions during childbirth.